Determination of β-agonists in pig feed, pig urine and pig liver using capillary electrophoresis with electrochemical detection

The fast separation capability of a capillary electrophoresis with electrochemical detection (CE–ED) system was demonstrated by determining five β-agonists including clenbuterol, metoprolol, ractopamine, isoxsuprine and salbutamol in several real samples. Factors influencing the separation and detection were examined and optimized. Under the optimum conditions, the five β-agonists could be well separated within 15 min at a separation voltage of 14 kV in a 100 mmoL H3BO3–Na2B4O7 running buffer (pH 9.0). This method was successfully used in the analysis of clenbuterol, metoprolol, ractopamine, isoxsuprine and salbutamol in pig feed, pig urine and pig liver, providing a useful method for monitoring the illegal use of β-agonists from growth promotion in food-producing animals.